LIN-67 functionally interacts with heterochronic miRNAs and regulates developmental timing in .

Temporal regulation of gene expression is required for developmental transitions, including differentiation, proliferation, and morphogenesis. In the nematode , heterochronic microRNAs (miRNAs) regulate the temporal expression of genes that promote animal development. The heterochronic miRNAs lin-4 and let-7 are required during different stages of larval development and are associated with the miRNA-specific Argonaute ALG-1.

Modeling neurodevelopmental disorder-associated human mutations in Argonaute .

MicroRNAs (miRNA) associate with Argonaute (AGO) proteins and repress gene expression by base pairing to sequences in the 3' untranslated regions of target genes. De novo coding variants in the human AGO genes and cause neurodevelopmental disorders (NDD) with intellectual disability, referred to as Argonaute syndromes. Most of the altered amino acids are conserved between the miRNA-associated AGO in and , suggesting that the human mutations could disrupt conserved functions in miRNA biogenesis or activity.

Modeling neurodevelopmental disorder-associated mutations in Argonaute .

MicroRNAs (miRNA) are endogenous non-coding RNAs important for post-transcriptional regulation of gene expression. miRNAs associate with Argonaute proteins to bind to the 3' UTR of target genes and confer target repression. Recently, multiple coding variants in the human Argonaute gene ( ) have been reported to cause a neurodevelopmental disorder (NDD) with intellectual disability (ID).

Global profiling and annotation of templated isomiRs dynamics across development.

microRNAs (miRNAs) are small non-coding RNAs that regulate gene expression through translational repression and mRNA destabilization. During canonical miRNA biogenesis, several miRNA isoforms, or isomiRs, are produced from a single precursor miRNA. Templated isomiRs are generated through Drosha or Dicer cleavage at alternate positions on either the primary or the precursor miRNAs, generating truncated or extended 5' and/or 3' miRNA ends.

Functional identification of microRNA-centered complexes in C. elegans.

microRNAs (miRNAs) are crucial for normal development and physiology. To identify factors that might coordinate with miRNAs to regulate gene expression, we used 2'O-methylated oligonucleotides to precipitate Caenorhabditis elegans let-7, miR-58, and miR-2 miRNAs and the associated proteins. A total of 211 proteins were identified through mass-spectrometry analysis of miRNA co-precipitates, which included previously identified interactors of key miRNA pathway components.

Single nucleotide substitutions effectively block Cas9 and allow for scarless genome editing in Caenorhabditis elegans.

In Caenorhabditis elegans, germline injection of Cas9 complexes is reliably used to achieve genome editing through homology-directed repair of Cas9-generated DNA breaks. To prevent Cas9 from targeting repaired DNA, additional blocking mutations are often incorporated into homologous repair templates. Cas9 can be blocked either by mutating the PAM sequence that is essential for Cas9 activity or by mutating the guide sequence that targets Cas9 to a specific genomic location.

An engineered, orthogonal auxin analog/AtTIR1(F79G) pairing improves both specificity and efficacy of the auxin degradation system in Caenorhabditis elegans.

The auxin-inducible degradation system in C. elegans allows for spatial and temporal control of protein degradation via heterologous expression of a single Arabidopsis thaliana F-box protein, transport inhibitor response 1 (AtTIR1). In this system, exogenous auxin (Indole-3-acetic acid; IAA) enhances the ability of AtTIR1 to function as a substrate recognition component that adapts engineered degron-tagged proteins to the endogenous C.

KH domain containing RNA-binding proteins coordinate with microRNAs to regulate Caenorhabditis elegans development.

MicroRNAs (miRNAs) and RNA-binding proteins (RBPs) regulate gene expression at the post-transcriptional level, but the extent to which these key regulators of gene expression coordinate their activities and the precise mechanisms of this coordination are not well understood. RBPs often have recognizable RNA binding domains that correlate with specific protein function. Recently, several RBPs containing K homology (KH) RNA binding domains were shown to work with miRNAs to regulate gene expression, raising the possibility that KH domains may be important for coordinating with miRNA pathways in gene expression regulation.

microRNA strand selection: Unwinding the rules.

microRNAs (miRNAs) play a central role in the regulation of gene expression by targeting specific mRNAs for degradation or translational repression. Each miRNA is post-transcriptionally processed into a duplex comprising two strands. One of the two miRNA strands is selectively loaded into an Argonaute protein to form the miRNA-Induced Silencing Complex (miRISC) in a process referred to as miRNA strand selection.

Protein Extract Preparation and Co-immunoprecipitation from Caenorhabditis elegans.

Co-immunoprecipitation methods are frequently used to study protein-protein interactions. Confirmation of hypothesized protein-protein interactions or identification of new ones can provide invaluable information about the function of a protein of interest. Some of the traditional methods for extract preparation frequently require labor-intensive and time-consuming techniques.

HRPK-1, a conserved KH-domain protein, modulates microRNA activity during Caenorhabditis elegans development.

microRNAs (miRNAs) are potent regulators of gene expression that function in diverse developmental and physiological processes. Argonaute proteins loaded with miRNAs form the miRNA Induced Silencing Complexes (miRISCs) that repress gene expression at the post-transcriptional level. miRISCs target genes through partial sequence complementarity between the miRNA and the target mRNA's 3' UTR.

Caenorhabditis elegans ALG-1 antimorphic mutations uncover functions for Argonaute in microRNA guide strand selection and passenger strand disposal.

MicroRNAs are regulators of gene expression whose functions are critical for normal development and physiology. We have previously characterized mutations in a Caenorhabditis elegans microRNA-specific Argonaute ALG-1 (Argonaute-like gene) that are antimorphic [alg-1(anti)]. alg-1(anti) mutants have dramatically stronger microRNA-related phenotypes than animals with a complete loss of ALG-1.

Mutations in conserved residues of the C. elegans microRNA Argonaute ALG-1 identify separable functions in ALG-1 miRISC loading and target repression.

microRNAs function in diverse developmental and physiological processes by regulating target gene expression at the post-transcriptional level. ALG-1 is one of two Caenorhabditis elegans Argonautes (ALG-1 and ALG-2) that together are essential for microRNA biogenesis and function. Here, we report the identification of novel antimorphic (anti) alleles of ALG-1 as suppressors of lin-28(lf) precocious developmental phenotypes.

Developmental decline in neuronal regeneration by the progressive change of two intrinsic timers.

Like mammalian neurons, Caenorhabditis elegans neurons lose axon regeneration ability as they age, but it is not known why. Here, we report that let-7 contributes to a developmental decline in anterior ventral microtubule (AVM) axon regeneration. In older AVM axons, let-7 inhibits regeneration by down-regulating LIN-41, an important AVM axon regeneration-promoting factor.

Complex network of Wnt signaling regulates neuronal migrations during Caenorhabditis elegans development.

Members of the Wnt family of secreted glycoproteins regulate many developmental processes, including cell migration. We and others have previously shown that the Wnts egl-20, cwn-1, and cwn-2 are required for cell migration and axon guidance. However, the roles in cell migration of all of the Caenorhabditis elegans Wnt genes and their candidate receptors have not been explored fully.

The C. elegans histone deacetylase HDA-1 is required for cell migration and axon pathfinding.

Histone proteins play integral roles in chromatin structure and function. Histones are subject to several types of posttranslational modifications, including acetylation, which can produce transcriptional activation. The converse, histone deacetylation, is mediated by histone deacetylases (HDACs) and often is associated with transcriptional silencing.

The C. elegans Frizzled CFZ-2 is required for cell migration and interacts with multiple Wnt signaling pathways.

Members of the Frizzled family of integral membrane proteins are implicated in many developmental events, including specifying cell fate, orienting cell and planar polarity, and directing cell migration. Frizzleds function as cell surface receptors for secreted Wnt proteins. We report here the isolation of a mutation in cfz-2, a Caenorhabditis elegans Frizzled gene.

Neural expression of the Huntington's disease gene as a chordate evolutionary novelty.

Huntington's disease is a progressive neuro-degenerative disorder in humans, which is scharacterized by onset of dementia, muscular ataxia, and death. Huntington's disease is caused by the expansion of the polyglutamine (polyQ) tract in the N-terminus of the HD protein (Huntingtin). CAG expansion is a dominant gain of function mutation that affects striated neurons in the brain (Cattaneo, 2003, News Physiol Sci 18:34).